Most computer users are familiar with Adobe Flash, the browser plug-in responsible for powering much of the Internet's multimedia content -- from YouTube videos and Flickr slideshows to addictive Web-based video games. Flash is popular because it works on any operating system and on many mobile devices, and because it handles media and graphics with aplomb.

Flash has some limitations, though. In order to run, its applications require a host application -- most often, your Web browser. That's where AIR, introduced last year, comes in. The primary reason to install AIR is to gain access to its framework and its powerful tool set that enables developers to create and deploy applications quickly to any platform.

AIR creates stand-alone applications that run from your desktop just like any other application. AIR apps are developed in much the same way that Flash applications are, providing developers with a new environment for creating powerful Web software that can run without a browser.

Despite AIR's impressive ability to blur the line between your desktop and the Web, AIR apps are by no means Web-only. In fact, some of them have nothing to do with the Web at all.

To get started using AIR applications, simply download and install AIR from Adobe. Once you've done that, downloading and opening an AIR app on your desktop will trigger the standard AIR installer -- think of these files as traditional setup applications, except that AIR handles the installation and one installer will work on both Macs and Windows PCs.